Medicinal
herbs and their essential oils (EOs) are of commercial and industrial
importance with diverse uses as forage and fiber crops, in food, cosmetics, perfumery
and chemical industries, and in traditional medicine due to their phytochemical
constituents and bioactivities. This chapter was aimed at documenting the
therapeutic properties of major secondary metabolites in EOs extracted from six
selected economically important medicinal herbs (Achillea millefolium L., Melissa officinalis L., Origanum
majorana L., Pelargonium
graveolens L'Hér. Rosmarinus officinalis L. and Thymus
vulgaris L.). Forty-five compounds (mainly
monoterpenes) were recorded as major compounds of the six medicinal herbs. The
compounds possess varying biological activities, which include antimicrobial,
anti-inflammatory, antioxidant and cytotoxicity properties. Other activities
reported were antinociceptive, neuroprotective effects, acetylcholinesterase
inhibition, anti-ulcerogenic, DNA protection, glutathione S-transferase
activity, chemoprotective, anti-depressant and sedative effects. The compounds
showed potential to be used as alternative agents as drugs, cosmetic
ingredients and food additives. Though some scientific evidence has confirmed
the use of these herbs in various industries, much work still needs to be done to
comprehend the therapeutic application of their EOs and phytoconstituents to
benefit from their full potential.
Keywords: Antimicrobial, Antioxidant, Cytotoxicity, Medicinal herbs, Phytochemicals.
